Currently, image forming apparatuses form toner images by developing an electrostatic latent image formed on a photoreceptor by using toner in a development apparatus. When the toner in the development apparatus decreases, the toner cannot be supplied to the photoreceptor. Therefore, the image forming apparatus is configured so as to supply toner as appropriate to the development apparatus from a toner bottle attachable to the main body of the apparatus.
The toner bottle includes a cylindrical casing, a spiral rib protruding on the inner peripheral surface of the casing, and an outlet for discharging the toner. In the toner bottle, when the casing rotates, the spiral rib conveys the toner to the outlet.
Typically, in the image forming apparatus, there is no configuration for directly detecting the remaining amount of the toner in the toner bottle. In the conventional image forming apparatus, the consumption amount of the toner is estimated based on the number of printed sheets, and the estimated consumption amount is subtracted from the capacity of the toner bottle to estimate the remaining amount of the toner.
As a result, in order to prevent the toner from being completely consumed, the image forming apparatus notifies a user that, for example, “the toner has run out” when the estimated remaining amount of the toner becomes equal to or less than a predetermined amount. However, at the time of the notification, a substantial amount of the toner is usually remaining in the toner bottle. Nevertheless, since the user needs to replace the toner with a new one, usable toner is thrown away and wasted.
Thereupon, for example, Patent Document 1 (identified below) describes a method of detecting a remaining amount of toner in a toner bottle by measuring the weight of the toner bottle. In the configuration in Patent Document 1, a toner bottle 5 is supported by a support member 52, and the weight is detected based on the movement of the support member 52 moving in a rotation direction about a fulcrum 54.    Patent Document 1: Japanese Patent Application Laid-Open No. 2014-85541.
However, with the configuration in Patent Document 1, in order to detect the weight, it is necessary for the toner bottle 5 and the support member 52 to move in the rotation direction with respect to a deflection member 55 about the fulcrum 54. Therefore, it is necessary to secure a space for the toner bottle 5 and the support member 52 to move, which consumes space and thus limits space saving. Moreover, in order to accurately measure the weight, it is necessary not to fix the toner bottle to surrounding members or to reduce the number of support points so that the toner bottle itself can move. However, the toner bottle has a weight of, for example, about 3 kg, and it becomes difficult to securely support the toner bottle if the number of support points is reduced.